Manatee is not design for WM, it's design for OS, so don't compare it with XMonad, it's really different thing with XMonad. Please watch Window split feature carefully in video to understand the difference, Manatee can split unlimited window for same application :

Manatee is distributed framework, it allowed you install extension don't need depend each other,
but it's easy to break if some package is older than core packages (manatee-core, manatee),
so please make sure all packages has update to newest version before you report bug to
manatee-user@googlegroups.com . Thanks! :)

manatee-core contain DBus protocol detail and toolkit use in other manatee packages.
manatee-welcome is use for show welcome page for manatee extension.
manatee contain daemon process,
Daemon process is root process to manage other manatee processes:
such as render application process' graphics for sandbox protected, window manage ... etc.
Daemon process just do manage job and don't running any special application code in it.
Other manatee-* package, such as manatee-editor, manatee-browser...etc running in
it's own process, you can write any code to implement your application,
just need follow some interface: